1. Field of the Invention
This invention pertains to a method of aligning the front and rear wheels of a vehicle in relation to the geometic center line of the vehicle, and to apparatus for practicing the method.
2. Description of the Prior Art
The apparatus which is present in the prior art and related to the method as well as apparatus for aligning front and rear wheels of a vehicle is exemplified in Carrigan U.S. Pat. No. 2,601,262 of June 24, 1952. In this patent light beam projectors are disposed near the front or steerable wheels, mirrors are carried on the rear of nonsteerable wheels, and screens are disposed at some distance from the front wheels so that charts may be projected directly upon the screens from the front and rear wheels. This apparatus to enable the aligning of vehicle wheels is expensive and quite complicated and in use calls for the bodily shifting of the vehicle to bring the vehicle axis into parallelism with the light beams projected rearwardly from the projectors positioned near the front wheels.
There are other more recent prior art examples utilizing mirrors mounted on the rear wheels of a vehicle, such examples being exemplified by Florer et al U.S. Pat. No. 4,095,902 of June 20, 1978, Lill U.S. Pat. No. 4,097,157 of June 27, 1978 and Hunter U.S. Pat. No. 4,265,537 of May 5, 1981.
Among the prior art of lesser pertinence, attention can be directed to MacMillan U.S. Pat. No. 3,091,862 of June 4, 1963 and Hunter U.S. Pat. No. 3,206,862 of Sept. 21, 1965.
The problems encountered in the prior art apparatus include such things as inability to align all four wheels of a vehicle to its geometric center line, failure to provide means which can accommodate vehicles having different wheel base dimensions, and failure to coordinate the relationship of the front and rear wheels with the geometric center line and with center point steering. It is recognized that the prior art apparatus tends to provide expensive instruments which complicate the job of determining wheel alignment conditions.